A Parameter-Free Two-Bit Covariance Estimator with Improved Operator Norm Error Rate
A Parameter-Free Two-Bit Covariance Estimator with Improved Operator Norm Error Rate
A covariance matrix estimator using two bits per entry was recently developed by Dirksen, Maly and Rauhut [Annals of Statistics, 50(6), pp. 3538-3562]. The estimator achieves near minimax operator norm rate for general sub-Gaussian distributions, but also suffers from two downsides: theoretically, there is an essential gap on operator norm …